Acute vs.Chronic Toxicity Pesticide Toxicity ■■■■ exposure.Effects appear within 24 hours of exposure Toxicity the ability of a substance to cause injury to a living system. exposure Most important factors:Quantity of ppesticdesin od water substance frequency of exposure Routes of Entry RISK TOXICITY x EXPOSURE "R器268ee胎i8pobn23skn -escoaeatonihmeda8oaggeteheoved Limit the possibility of poisoning by preventing and/or limiting exposure 一s8yaghregndgronabsowbmore Exposure=amount and route of Inhalation-Breathe in particles-2nd most exposure common route -Dry formulations.fumigants greatest risk ■Oral-ingestion Personal Protective Equipment Measuring Acute Toxicity Requirements are based on the route of Lethal Dose Fifty(LD0) entry,toxicity and formulation of the pesticide. oral exposure Ss%28eSanoegeengh ppm -Waterproof boots-pant legs over boots -Low LDso-high toxicity 器n0-aey0esa9o9eso Lethal Concentration Fifty(LCso) -Based on inhalation exposure Dust mask or cartridge respirator Measured in mg/L 11 Pesticide Toxicity Toxicity = the ability of a substance to cause injury to a living system. Most important factors: Quantity of substance & frequency of exposure Acute vs. Chronic Toxicity „ Acute Toxicity – how poisonous a pesticide is to a organism after a single, short-term exposure. Effects appear within 24 hours of exposure. – Used as basis for warning statement on label „ Chronic Toxicity – delayed poisonous effect after 3+ months of continuous or occasional exposure – Repeated exposure to pesticides in food, water & air. RISK = TOXICITY x EXPOSURE „ Limit the possibility of poisoning by preventing and/or limiting exposure „ Exposure = amount and route of exposure Routes of Entry „ Dermal – pesticide absorbed through skin – most common route for poisonings – Gets on skin during mixing/loading, or when pesticide-contaminated clothing is not removed promptly – Eyes, eardrums, scalp and groin absorb more rapidly than rest of body „ Inhalation – Breathe in particles – 2nd most common route – Dry formulations, fumigants greatest risk „ Oral – ingestion – Major absorption site = small intestine – Hands not washed before eating/smoking; pesticides stored in food containers Personal Protective Equipment „ Requirements are based on the route of entry, toxicity and formulation of the pesticide. – Long-sleeved shirt, long pants or coveralls - tightly woven fabric or waterproof material – Rubber gloves – unlined/elbow length. Shirt sleeves worn over gloves – Waterproof boots – pant legs over boots – Eye Protection – safety glasses/goggles or face shield – Dust mask or cartridge respirator Measuring Acute Toxicity „ Lethal Dose Fifty (LD50) – Amount of pesticide that has killed 50% of the test animal population via dermal or oral exposure. – Measured in # milligrams per kilogram of the animal’s body weight = ppm. – Low LD50 – high toxicity „ Lethal Concentration Fifty (LC50) – Based on inhalation exposure – Measured in mg/L